Process for producing carboxylic esters from organo manganese compounds



United States Patent 1 Claim. (Ci. zoo-410.9

This application is a division of application Serial No. 2,825, filedJanuary 18, 1960, now Patent No. 3,081,324, granted March 12, 1963.

This invention relates to organic compounds of manganese, moreparticularly to such compounds in which a plurality of carbonyl groupsis present. This invention further relates to methods of making andusing these compounds.

Among the objects of the present invention is the provition of novelcompounds of the above type which are simple to form and which havedesirable uses.

The above as well as additional objects of the present invention will bemore fully understood from the following description of several of itsexemplifications.

The compounds of the present invention are organoyl manganesetetracarbonyl ammonias in which not more than two of the ammoniahydrogens are substituted by hydrocarbon radicals having up to 13carbons each, and the organoyl radical has up to 13 carbon atoms.

These compounds are very cOnveniently formed by merely mixing ahydrocarbyl manganese pentacarbonyl with an ammonia corresponding to theone desired in the final compound. The hydrocarbyl manganesepentacarbonyls as well as methods for making them are described in U.S.Patent 2,913,413, granted November 17, 1959, and the pertinentdisclosures of the preparation of these pentacarbonyls is incorporatedherein as though fully set forth.

Although compounds of the present invention can have more than 13carbons in any of the hydrocarbon radicals substituted for the ammoniahydrogen as well as in the organoyl radical, the use of more than 13carbons in any one group is not preferred. The organoyl radicals can beof the acyl or aroyl types although those of the acyl type more readilyform the desired compounds, and the compounds thus formed react moresmoothly and efiiciently.

The reaction that forms the compounds of the present invention takesplace at room temperature as well as at temperatures as much as 70 aboveand below room temperature. In the interest of simplicity, it is best tooperate at temperatures of from about -35 to 50 C. The manganesepentacarbonyls used as starting material for producing the desiredcompounds are generally low melting solids and they are more efficientlyreacted by placing them in liquid form, as by dissolving them in asuitable solvent or by melting them. Suitable solvents are hydrocarbonssuch as gasoline, iso-octane, petroleum ether and n-decane, ethers suchas tetraaydrofurane, diethylether, dipropylether, ethyleneglycolmonomethylether, diethyleneglycol dimethylether, ethyleneglycoldiethylether, diethyleneglycol monoethylether, diethyleneglycoldibutylether, ethanol, propanol, butanol, acetone, methylethylketone andmethylisobutyl ketone. In general, all normally liquid hydrocarbons andnormally liquid ethers and alcohols are effective for this purpose.

The reaction of the ammonia with the hydrocarbyl manganese pentacarbonylgenerally takes at least about /2 hour to go to completion. As a matterof precaution the reaction can be continued for as much as 20 hours ormore to assure good yields in the event one of the reactants is in thesolid phase, or contaminants slow down the reaction velocity. Thefollowing examples, where all parts are parts by weight unless otherwisespecified, show some of the variations in the reaction technique.

EXAMPLE I C yclohexylamine acetylmanganese tetracarbonyl Methylmanganesepentacarbonyl (2.1 g., 0.010 mole) and cyclohexylamine (1.48 g., 0.015mole) was dissolved in ml. of tetrahydrofuran. The solution was stirredin a nitrogen atmosphere at room temperature for 4 hours. No gasevolution was observed. The reaction mixture was poured into 750 ml. ofice water and the resulting yellow precipitate (2.9 g., 93%) wasfiltered off, washed with water and dried. The product, recrystallizedfrom ether, melting at 97.0-97.5 C. with gas evolution. It was solublein carbon tetrachloride, chloroform and benzene, and sparingly solublein iso-octane and methanol. The infrared spectrum (carbon tetrachloridesolution) showed bands at 4.8 4.95 1, 5.05,u, and 5.15 in themetallocarbonyl region and a ketonic carbonyl band at 6.2 Its molecularweight was determined cyroscopically, and it was subjected to elementalanalysis, with the following results:

Calculated for C H MnNO C, 46.6; H, 5.21; Mn, 17.8; N, 4.53; mol. wt.,309. Found: C. 46.6; H, 5.37; Mn, 17.9; N, 4.23; mol. wt., 295.

EXAMPLE II Ammonia acetylmanganese tetracarbonyl A mixture ofmethylmanganese pentacarbonyl (4.0 g., 0.019 mole) and liquid ammonia(200 ml.) was refluxed with stirring for two hours. Excess ammonia wasallowed to evaporate slowly. A greenish-yellow solid (4.11 g., 95%)remained in the reaction vessel. Recrystallization from diethylethergave 3.65 g. of ammonia acetylmanganese tetracarbonyl, light yellowcrystals, melting at 95.5-96.0 C. with decomposition.

Arzalysis.Calculated for C H MnNO C, 31.8; H, 2.69; Mn, 24.2; N, 6.17.Found: C, 32.4; H, 2.70; Mn, 24.4; N, 6.16.

EXAMPLE III N-methylcyclohexylaminc acetylmanganese tetracarbonylMethylmanganese pentacarbonyl (5.0 g., 0.024 mole) andN-methylcyclohexylamine (4.0 g., 0.036 mole) were dissolved in 50 ml. oftetrahydrofuran and stirred at room temperature for two hours. Excesssolvent was evaporated in vacuo. The residues were cooled in Dry Icegiving 3.1 g. (40%) of yellow crystals. The product, recrystallized frompetroleum ether (B.P. 38.42 C.), melted at 7374 C.

Analysis. Calculated for C H MnNO C, 48.3; H, 5.60; Mn, 17.0; N, 4.33.Found: C, 48.3; H, 5.58; Mn, 17.4; N, 4.44.

EXAMPLE IV Aniline acetylmanganese tetracarborzyl Methylmanganesepentacarbonyl (3.0 g., 0.014 mole) and aniline (2.0 g., 0.022 mole) weredissolved in 50 ml. of tretrahydrofuran and kept under nitrogen at roomtemperature for 75 hours. Then the solution was poured into 400 ml. ofice water, giving a yellow precipitate, which after washing and dryingweighed 1.72 g. (38%). Recrystallization from ether gave yellowcrystals, melting at 8384 C.

Analysis-Calculated for C H MnNO C, 47.6; H, 33.3; Mn, 18.1; N, 4.62.Found: C, 46.6; H, 33.3; Mn, 17.8; N, 4.70.

' desired products tend to EXAMPLE V Cyclohexylamine benzoylmanganesetetracarbonyl Phenylmanganese pentacarbonyl (2.0 g., 0.0074 mole) andcyclohexylamine (0.80 g., 0.0081 mole) were dissolved in 35 ml. ofdiethylether and stirred at room temperature for 1.5 hours. Theresulting orange solution was cooled in Dry Ice giving 0.25 g. (12%recovery) of phenylmanganese pentacarbonyl. The mother liquor wasconcentrated, cooled in Dry Ice and filtered, giving 087 g. of anorange, heterogeneous, solid mass and an orangebrown viscous filtrate.The filtrate was dried over potassium hydroxide pellets and paraffinflakes, giving 0.70 g. of a tacky, brown solid. Repeated extraction ofthis with petroleum ether, concentration of extracts, and cooling gave0.23 g. (10% yield) of crude cyclohexylamine benzoylmanganesetetracarbonyl. Recrystallization from petroleum ether gave a yellowsolid, melting at 75-78 C.

EXAMPLE VI Aniline benzoylmanganese tetracarbonyl Phenylmanganesepentacarbonyl (2.72 g., 0.010 mole) and aniline (1.02 g., 0.011 mole)were dissolved in 30 ml. of ether and allowed to stand at roomtemperature under nitrogen for 163 hours. The resulting yellow-brownsolution was filtered and cooled in Dry Ice giving 0.83 g. of yellowcrystals. Fractional crystallization from petroleum ether gave 0.22 g.of benzoylmanganese pentacarbonyl and 0.61 g. of tarting material. Themother liquor was concentrated and cooled giving 0.50 g. of startingmaterial (total recovery of 41%). After further concentration the motherliquor was treated with iso-octane precipitating a dark yellow solid(0.23 g., 10%). The crude product melted at 7879 C.

By way of comparison neither trimethylamine nor pyridine could be madeto react with the hydrocarbyl manganese pentacarbonyls to form thedesired products.

The above formation reactions do not require the presence of anymaterials other than the reactants, and no special treatment is neededas long as these reactants are caused to contact each other. After about/2 hour of such contact even at temperatures as low as 40 C., arecoverable yield of product is obtained. Reaction temperatures above100 C. are not desirable because the decompose at these temperatures,particularly when in concentrated form. These products are generally lowmelting crystalline solids with fairly strong color, very slightlysoluble in petroleum ether,.

cold iso-octane and cold methanol when the ammonias range up todi-tridecylamine, omega-phenyl amylamine, 4 hexyl cyclohexyl amine andbeta heptyl piperidine. Other ammonias that are suitable for thepurposes of the present invention include methylamine, ethylamine,dipropylamine, cyclopentylamine, amino cyclohexadiene- 2,4, allylamine,naphthylamine, N-tetrahydroqu-inoline, and pyrimidine. Ammonia itselfand aliphatic-substituted ammonias react most rapidly to form thedesired compounds.

The hydrocarbyl groups in the original manganese pentacarbonyl can rangeup to 12 carbons in size and preferably are alkyl groups inasmuch as theyields are much lower with aryl grupS.. Good results can be obtainedwith hydrocarbyl groups such as phenyl, toluyl, xylyl, dodecyl,p-dicyclohexyl, hexyl, pentyl, butyl and vinyl. As a result of thereaction, the hydrocarbyl groups have a carbonyl group added and areaccordingly converted to hydrocarboyl groups with one additional carbon.

The hydrocarboyl manganese tetracarbonyl ammonias of the presentinvention are cleaved by strong alkali such as sodium methylate to splitoff the hydrocarboyl portion from the balance of the molecule. Themethylate of the hydrocarboyl group is thus formed, corresponding to themethyl ester of the carboxylic acid that has an OH group connected tothe hydrocarboyl group. With other alcoholates, the corresponding estersof the same acid are formed. With sodium hydroxide the unesterified acidis formed.

The remainder of the split molecule appears to be an ammonia complexNaMn(CO) ammonia. When treated with methyl iodide, this remainderdisproportionates to give methyl manganese pentacarbonyl along withhisammonia iodomanganese tricarbonyl.

The above cleavage reactions establish the structure of the originalhydrocarboyl manganese tetracarbonyl ammonias and show that in theformation of these compounds one of the carbonyl groups of thepentacarbonyl reactant becomes linked to the hydrocarbyl radical. Thisshift is reversed in the presence of strong acid, and the hydrocarbylmanganese pentacarbonyl thus recovered along with the corresponding saltof the amine. Both their cleavage and the reversal of their formationreactions provide valuable uses for the compounds of the presentinvention.

The cleavage provides one simple technique for the direct formation ofesters from hydrocarbon halides or sulfates. These starting materialsreadily react with NaMn(CO) as shown in Examples XXX and XXXI of U.S.Patent 2,913,413, to give the hydrocarbyl manganese pentacarbonyl usedas a reactant to form a hydrocarboyl ammonia of the present invention.Although that Example XXXI describes the reaction of a hydrocarboylhalide with the above sodium compound, hydrocarbyl halides react in thesame way although less vigorously. The hydrocarboyl ammonia can then becleaved with or without prior purification, to form the desired ester.Any other alkali metal salt of a hydroxy hydrocarbon can be used in thecleavage, as for instance sodium ethylate, lithium beta phenyl ethylate,potassium cyclohexylate, rubidium octadecylate, etc. The following is atypical cleavage run.

EXAMPLE VII Cleavage of cyclohexylamine acetylmanganese tetracarbonylwith sodium methoxide To the cyclohexylamine acetyl manganesetetracarbonyl of Example I (10.0 g., 0.032 mole) dissolved in 300 ml. ofmethanol there was added dropwise a solution of sodium methoxide (1.75g., 0.032 mole) with ice cooling. After the addition, the solution wasstirred at room temperature for 2.5 hours. Approximately ml. of solventwas distilled off and the fraction boiling in the range of 53.2-63.9 C.was identical to an authentic methanol-methylacetate azeotrope.Refractive index data showed that the product contained 1.6 g. ofmethylacetate (69% of theory).

Twelve milliliters of the azeotrope was refluxed with 4 ml. ofbenzylamine and 0.1 g. of ammonium chloride for 42 hours. Methanol wasthen distilledoff, and the residue neutralized with aqueous HCl. Etherextraction and evaporation gave white crystals which melted at 6364 C.after recrystallization from n-hexane-ether. No melting point depressionwas observed with an authentic sample of N-benzylacetamide.

The ammonia fraction of the cleavage remained in the reaction mixtureafter the first distillation was treated with methyl iodide (13.6 g.,0.096 mole) and stirred at room temperature for 2.5 hours. The solventwas evaporated in vacuo, leaving 60 ml. of a brown solution. Methylmanganese pentacarbonyl (0.48 g.) sublimed out of the reaction mixtureduring the evaporation. Yellowbrown flakes of bis-cyclohexylamineiodomanganese tricarbonyl crystallized out of the brown solution afterstanding overnight. After recrystallization from chloroform the solidmelted at 192.0192.5 C. with decomposition.

Analysis.-Caleulated for C H IMnN O C 38.8; H, 5.65; I, 27.4; Mn, 11.9;N, 6.04. Found: C, 39.3; H, 5.89; I, 27.9; Mn, 11.6; N, 6.03.

Similar cleavages produce hexadecyl octanoate, 4- phenyl cyclohexylbenzoate, beta naphthylate heptanoate.

By selecting non-azeotropic cleavage solvents or even usingnon-azeotropic diluents that are not solvents for the cleavagereactants, the distillation of the ester is simplified.

The hydrocarboyl manganese tetracarbonyl ammonias of the presentinvention are also good gasoline additives since they produce effectiveoctane rating increases notwithstanding their low solubility in thegasoline. At a concentration of 1 pound per thousand barrels anilineacetylmanganese tetracarbonyl will by Way of example substantially raisethe octane rating of unleaded 100 octane gasoline, and will also producea substantial increase in the octane rating of gasoline containing 3 cc.of tetraethyllead per gallon and having an octane rating of 96.

In the formation of the hydrocarboyl manganese tetracarbonyl ammonias itis not necessary to use a nitrogen atmosphere. The reaction atmospherecan be ordinary air Without changing the results.

Obviously many modifications and variations of the present invention arepossible in light of the above teachings. It is therefore to beunderstood that, within the scope of the appended claim, the inventionmay be practiced otherwise than as specifically described.

What is claimed is:

The method for the conversion of a compound selected from the classconsisting of hydrocarbon halides and bydrocarbon sulfates having up to12 carbon atoms per hydrocarbon group, to esters of hydroxy hydrocarbonswherein the hydrocarbyl radical of the hydrocarboncarboxy portion ofsaid ester is the hydrocarbon group of said compound, in which methodsaid compound is converted to the corresponding hydrocarbyl manganesepentacarbonyl by reacting said compound with sodium manganesepentacarbonyl, thereafter reacting the hydrocarbyl manganesepentacarbonyl thereby produced with a reactant selected from the classconsisting of primary and secondary amines wherein the hydrocarbonradicals of said amines have up to 13 carbon atoms, and ammonia, to forma corresponding intermediate selected from the class consisting ofhyrocarboyl manganese tetracarbonyl ammonias, hydrocarboyl manganesetetracarbonyl primary amine compounds, and hydrocarboyl manganesetetracarbonyl secondary amine compounds, in which the hydrocarboyl grouphas a CO group linking the original hydrocarbyl group to the manganeseatom, and then cleaving said intermediate with an alkali metal salt of amonohydroxy hydrocarbon having up to 13 carbon atoms per molecule, toform the ester of said monohydroxy hydrocarbon with a carboxylic acidcorresponding to said hydrocarboyl group.

No references cited.

CHARLES B. PARKER, Primary Examiner.

DANIEL D. HORWITZ, Examiner.

